x1 = rand(5000,1)*2 - 1; 
y1 = rand(5000,1)*2 - 1; 

r2 = 1; 
theta = 0 : pi/100 : 2*pi;
x2 = r2 * cos(theta); 
y2 = r2 * sin(theta);

plot(x1,y1,'r.',x2,y2,'-');




r1 = rand(5000,1);
theta = rand(5000,1);
x1 = r1 .* cos(theta * 2*pi); 
y1 = r1 .* sin(theta * 2*pi);

r2 = 1;
theta = 0 : pi/100 : 2*pi;
x2 = r2 * cos(theta); 
y2 = r2 * sin(theta);

plot(x1,y1,'r.',x2,y2,'-');




r1 = rand(5000,1);
theta = rand(5000,1);
x1 = sqrt(r1) .* cos(theta * 2*pi); 
y1 = sqrt(r1) .* sin(theta * 2*pi);

r2 = 1;
theta = 0 : pi/100 : 2*pi;
x2 = r2 * cos(theta); 
y2 = r2 * sin(theta);

plot(x1,y1,'r.',x2,y2,'-');




A = rand(5000,1);
x1 = sqrt(A) .* cos(A * 2*pi); 
y1 = sqrt(A) .* sin(A * 2*pi);

r2 = 1;
theta = 0 : pi/100 : 2*pi;
x2 = r2 * cos(theta); 
y2 = r2 * sin(theta);

plot(x1,y1,'r.',x2,y2,'-');